p.s. sometimes you may have to turn the little screw in the throttle plat when the secondary stop sits..If you dont have front and reat idle screws then take the carb off and flip it upside and you will see the flat blade screw,turn it ccw 1/2 turn...idle mixture screws i only turn them 1/2 turn..any more then that you will just be loading up at idle..

+1

I have seen a number of recommendations to block off the secondary power valve. I bought a carb from Patrick at Pro Systems and he keeps telling me that I should keep my secondary power valve. What's the consensus on secondary power valves?

I have a 540 and updated the carb with a new 850 Holley p/n # 80443, PV front and back jets 88's & 96's, right out of the box I had A/F readings of 13.1 cruise ........ runs great Idle is 13.6 WFO 12.7

It's a gen 6 block, I was having fuel pressure issues b/f but found air leak in small fuel filter , once removed boat ran to 5050 rpm perfect w/ old 750 w, 77/87 jets, I bought the 800 I between everything for a nicer bigger carb and now the guy is telling me to send it back, I tried diff metering blocks, and using carb cleaner on passage ways but no luck appreciate all the help ill look for bleed passage ways w carb off and try that

Ps the guy who I bought carb off acted if thou he forgot holes in throttle blades but I don't recall thoses in my old 750 ...u guys have holes?

If you do what mrfixxall said above about flipping the carb upside down and adjusting the secondaries you don't need the holes. What I do when I have the carb off is put in a hex set screw to replace the secondary adjusting screw and install the screw hex up so I can adjust it with the carb on from the top.

You only need the holes if you are running a big cam. You need to make sure the throttle blades are within the fuel transfer slots preferably in the middle and balanced primary and secondary.

+1
I have had to adjust these on many different applications, and this is the way to get your idle up so your primarys are within the idle slots. I bet if you compare the 2 - 800's you can see the difference in the secondary opening.
Blue Thunder, I love your idea of the hex set screw pointing up!

fixx
 

all the holes do in the throttle blades is help the idle circuit if you have a huge can where vacume is vary low..they are usually rite in front of the the little slots are that the fuel flows from so the engine can idle..

When the carb is up side down the holes in the circle part index throttle blade 3of 4 are clogged , my old carb they squirt no problem... I couldn't get them clear w carb cleaner will try compress air Monday...